-blast. A suffix meaning an immature precursor cell of the type indicated by the preceding word. [G. blastos, germ]. immature precursor cell type; the cell type is denoted by the preceding syllables, e.g. osteoblast.
(plural defining moments) A moment in time that defines something, such as a person's success or failure, achievement or demise, talent, etc. A point at which the essential nature or character of a person, group, etc., is revealed or identified.
lasting but a moment; very brief; fleeting: a momentary glimpse. 2. that might occur at any moment; ever impending: to live in fear of momentary annihilation. 3. effective or recurring at every moment; constant. Origin of momentary.